Impact ore mill

ABSTRACT

A mill is provided for crushing ore by impaction which has a rotor and a drum driven in the same direction at varying speeds. The axis of rotation of the drum can be shifted relative to the axis of rotation of the rotor to selectively adjust the spacing between beater blades on the rotor and impact plates carried by the drum. Seals are provided between the rotor shaft and the side walls of the drum to allow this relative movement to take place. The beater blades are each made up of identical parts which can be rearranged on the rotor to compensate for wear.

United States Patent 1191 1111 3,834,632 ocksteader [45] S t, 10, 1974 IMPACT ORE MILL 3,353,947 11/1967 Kramer 241/792 x [76] Inventor: Wesley E. Docksteader, P. O. Box FOREIGN PATENTS OR APPLICATIONS 753, Grand Forks, Canada 754,537 3/1967 Canada 241/74 Jan. 8, France [21] Appl. No.1 321,723 Primary Examiner-Roy Lake Assistant Examiner-Howard N. Goldberg [301 Foreign Application Priority Data Attorney, Agent, or FirmFetherstonhaugh & Co.

Jan 18, 1972 Canada 132802 ABSTRACT 52 us. Cl. 241/187, 241/189 R, 241/231, A mill is Provided for crushing Ore y impaction which 24 3 has a rotor and a drum driven in the same direction at 51 1111.01. B02 13/06, B02c 13 30 varying Speeds The axis of rotation of the drum can [58] Field of Search 241 /73 74, be Shifted relative to the axis of rotation of the rotor 241/792 79.3, 37 7 37 188 R, 9 R, to selectively adjust the spacing between beater blades 191, 95 230431 286 on the rotor and impact plates carried by the drum. Seals are provided between the rotor shaft and the [56] References Cited side walls of the drum to allow this relative movement UNITED STATES PATENTS to take place. The beater blades are each made up of 2 684 206 7/1954 Z a l 241/74 X identical parts which can be rearranged on the rotor e e 3,021,008 2/1962 Christian 241 /87 x to compensate for wear 3,235,188 2/1966 Bradley 241/73 X 10 Claims, 6 Drawing Figures PATENTEDSEP 1 01974 3. 834.632

sum 2 0r 4 FEE- I 4A MA IMPACT ORE MILL My invention relates to machines for crushing ore and more particularly to a machine for milling batches of ores which vary in size.

The operators of small mines are particularly interested in milling machines which are versatile enough to handle a variety of free milling ores. It is important that the mill be readily adjustable to reduce one type of ore after a run of crushing ore of another type otherwise lengthy and therefore costly shut-down periods are required. Desirably, bearings as well as other operating parts of the mill should be protected from the highly abrasive effects of the milled ore and those parts which actually engage the ore during the crushing operation and which inevitably become worn, should be interchangeable in order to reduce operating costs. Most lightweight ore mills, currently in use in small mines, lack some or all of these basic requirements.

The ore mill I have designed can be adjusted quickly and easily to vary the spacing between the ore impacting parts and this allows the machine to be set to handle ore of a particular size which considerably improves production. In order to achieve this adjustment, the ore-impacting rotor and drum of the present mill are made radially movable with respect to one another and a simple and effective seal is provided therebetween to allow this relative movement to take place. The rotor has beater blades which are divided and secured in such a way that whenever a blade part becomes worn to a degree where it is no longer effective, it can be exchanged for an unworn part of the same type or another blade.

In drawings which illustrate a preferred embodiment of the invention,

FIG. 1 is a perspective view of my impact ore mill,

FIG. 2 is a vertical section with parts purposely omitted for the sake of clarity,

FIG. 3 is a transverse section taken on the line 3--3 of FIG. 2,

FIG. 4 is a side elevation, partly broken away, and again with some parts omitted,

FIG. 5 is an enlarged side elevation showing the sealing means, and

FIG. 6 is a further enlarged section taken on the line 6--6 of FIG. 5.

Referring to the drawings, the numeral 10 in FIG. 1 indicates generally an impact ore mill embodying the improvements of the present invention. Preferably, the mill I0 is mounted on a ski'd frame 12 so that it can be readily towed over rough terrain if necessary. The skid frame 12 supports a base 14 formed by a pair of transversely spaced pedestals MA on which 'a beater-type rotor 16 (FIG. 2, for example) and an enclosing drum 18 are rotatably mounted. Drive means generally indicated at 20, and including an electric motor 21, is provided to rotate both the rotor 16 and the drum 18 in the direction of arrow 22, see FIG. 1, and during this rotation the drum and rotor co-operate to reduce ore to the desired degree of fineness.

The ore which is to be processed by the mill 10 is dumped into twin hoppers each designated by the numeral 24, these hoppers being supported on a framework 26 carried by the skid frame 12. The hoppers 24 are adapted to feed ore into twin conveyors 28 disposed one on each side of the drum l8, and these conveyors deliver the ore into the revolving drum 18 through infeed spouts 30. Eventually, the divided ore is discharged from the drum 18 on to a launder 32 which delivers the milled ore to a separation table (not shown) for further processing.

The rotor 16 has a horizontal driven shaft 34 and means generally indicated at 35 is provided for mounting said rotor shaft on the pedestal base 14. As shown in FIGS. 1 and 2, the mounting means 35 comprises a pair of bearings 37 in which the shaft 34 is joumalled, there being one such bearing carried ontop of each pedestal 14A. The drive means 20 includes a beltdriven pully 38 (FIG. 1 only) which is secured to one end of the shaft 34 and the drive train from the motor 21 to said shaft is such that the rotor 16 can be rotated at quite a high rate of speed.

The drum generally indicated at 18 is shown to comprise side walls 40 and a connecting peripheral wall 41, the three walls being suitably boltedtogether.Preferably, the drum 18 is constructed in two separatable halves as indicated by line 42 in FIG. 3 whereby one half can be removed from the other if necessary to provide access to the interior of the drum. Side walls 40 are each provided with an concentric opening 44 (FIG. 6) through which the shaft 34 projects. The peripheral wall 41 has a plurality of rectangular openings 45, see FIG. 3, which are circumferentially spaced around the drum to extend between the side walls 40. Each opening 45 is covered by a classifier screen 46 of a suitable mesh. On the inner surface of the wall 41, the adjacent each opening 45, a transversely extending impact plate 48 is secured to extend inwardly and project partly across said opening as shown best in FIG. 3. The inner end of the plates 48 are braced against the drum wall 41 by means of transversely spaced rods 49.

Ore deposited in the drum 18 through the infeed spouts 30 is thrown against the impact plates 48 by the action of the rotor 16 as will be described later and is reduced or disintegrated to a degree of fineness which will allow the material to pass through the screens 46 and be discharged on to the launder 32.

In order to prevent clogging of the screens 46, a high pressure spray of water is directed against the outer periphery of the drum 18. This is done by means of apipe 54 fitted with a spray head 55, see FIG. 1. The U- shaped pipe 54 is mounted on the pedestals 14A so as to connect with a suitable source of pressurized water (not shown) and said pipe is fitted with a control valve 56. By adjustment of the valve 56, the water spray can be controlled to keep the screens 46 clear of the reduced ore and-also to provide a properly proportioned mixture of fines and water for discharge as a slurry from the mill 10. A water guard 58 (FIG. 1) is mounted over the drum l8 and the spray head 55 to prevent water from discharging outwardly of the mill. Preferably, the guard 58 encloses a major portion of the circumference of the drum and is a two-part structure with one part being shown by dotted lines only in FIG. 1.

As shown in FIGS. 2 and 3, the rotor 16 is provided with an elongated hub 62 which is non-rotatably mounted on the shaft 34. A pair of transversely spaced spiders 63 are secured to opposite ends of the hub 62 and these spiders each have a suitable number of radial spokes 64. The outer ends of the spokes 64 are connected by cross bars 66 and each bar is provided with a recess 67 on the leading edge thereof. Seated in each recess 67, is a beater blade 68 which is secured to the made of a good quality, hard wearing steel, which will stand up to hard use for lengthy periods.

The ore which is reduced by the mill is screened before it is fed into the drum 18 and the material processed during a particular run of the machine may have a maximum diameter of, say, one inch with the usual quantity of smaller ore. Another batch of a different type of ore processed during a later run may be three quarter inch and less. If the mill 10 is to run smoothly and efficiently to ensure a high rate of production, it is extremely important that proper clearance be provided between the impact plates 48 and the beater blades 68 for each batch of ore. For example, it has been found that with 1 inch minus ore, the plate to blade clearance should be approximately one and one quarter inches while the three quarter minus ore requires a clearance of about 1 inch. In this ore mill, provision is made for adjusting the axis of rotation of the rotor 16 radially relative to the axis of rotation of the drum 18 to provide the necessary clearance and preferably this adjustment is incorporated into mounting means 71 for the drum 18. However, it should be noted that the adjustment almost as readily be part of the mounting means 35 for the rotor since the bearings 37 might conveniently be made vertically adjustable on the pedestal base 14.

Referring now particularly to FIGS. 2 and 4, the drum mounting means 71 is shown to comprise a pair of bearings 72 and a second pair of bearings 73 which are secured to pedestal members 74 spaced below the top of the base 14. The two bearings 72, which are located one on each side of the drum 18, are suitably bolted to the members 74 and each bearing journals a stub shaft 76 on which a circumferentially grooved wheel 77 is mounted. Both the bearings 73 are secured to their members 74 by bolts 80 which project through longitudinally extending slots 81 (FIG. 4) formed in said pedestal members. Thus, the pair of bearings 73 are adjustable towards and away from the pair of bearings 72. A stub shaft 83 is joumalled in each bearing 73 and is fitted with a wheel 84. The wheels 84 are similar to and aligned with the wheels 77.

Trunnion rings 87 are mounted in the wheels 77 and 84 on opposite sides of the drum 18 so as to rotate freely in the wheels. The rings 87 are suitably bolted as at 88 or otherwise fastened to the side walls 40 in a position concentric to the openings 44 therein. Thus, the rings 87 sit in the pulley-like wheels 77 and 84 and are held against jumping out by the considerable weight of the drum 18. The shaft 76 on the right side of the mill, see FIG. 1, is the output shaft of a reduction gear 90 which has an input shaft fitted with a pulley 91 and this pulley is belt connected into the drive means 20. Drum 18 is rotated by the means 20 in the same direction as the rotor 16 but at a much slower speed, the preferred ratio being 1 to 100.

Whenever it is necessaryto adjust the spacing between the blades 68 and the innermost edges of the plates 48, it is a simple matter to do so by virtue of the adjustable mounting means 71. This adjustment is accomplished by temporarily slacking off the bolts 80 which hold down the bearings 73 and moving the wheels 84 towards or away from the wheels 77 according to whether the spacing is to be increased or decreased. This adjustment raises or lowers the drum 18 and it is the blade-to-plate spacing at the bottom of the drum (indicated by letter A in FIG. 3) which is set at bar 66 by means of bolts 69. Each beater blade 68 is l inch for three quarter minus ore and at one and one I quarter inches for 1 inch minus ore. The ore deposited in the drum through the spouts 30 naturally falls to the bottom of the drum and the necessary clearance must be provided for the largest pieces before reduction begins, hence the need for clearance at this point.

Since the rotor 16 and drum 18 are adapted to be moved vertically relative to one another, a special seal is required for the shaft 34 where it projects through.

the drum wall opening 44. A particularly effective sealing means is provided for each opening 44 and one such means is shown best in FIGS. 5 and 6. In FIG. 6 it will be seen that the opening 44 is much larger than the shaft 34 and a cover plate 102 is provided to form a closure for said opening. The circular cover plate 102 has a hole 103 for the shaft 34 and a packing gland 104 encloses the shaft alongside this hole, the gland being held in place by a divided collar 106 which is secured to the plate 102 by means of bolts 108.

Surrounding the opening 44 is an annular seal 110 which is secured to the wall 40 by a ring 111. A relatively large annular seal 114 is secured to the inner face of the cover plate 102 near rim 115 thereof and this seal is spaced from the small seal 110 to provide an annular mud channel 116. The seal 114 is received in a two-part or divided annular collar 117 which is secured to the wall 40 by bolts 1 17A. Collar 117 is substantially U-shaped in cross section as shown in FIG. 6 and an annular mud channel 118 is provided between flanges 1 19 and 120 of said collar. A gasket 123 separates the collar 1 17 from the wall 40 and the flange 120 has sliding engagement with the cover plate 102. An identical sealing means 100, which is not illustrated in the drawings, is provided on the opposite side wall 40 to seal the opening 44 thereof.

This particular construction for the two sealing means 100 allows the rotor 16 and drum 18 to rotate in the same direction but at different speeds but, more importantly, it allows the drum to move vertically with respect to the rotor by adjustment of the mounting means 71 as previously described. In addition, the means 100 will serve to trap any of the slurry which might escape past the seals 110 and 114. Some of this watery or mud-like fluid will be trapped in the channel 116 but a greater amount will be contained in the channel 118. The mixture reaching the channel 118 dries out and settles in the form of mud which conveniently can be cleared away periodically by removal of the two-part collar 117 from the wall 40.

It has been found that the maximum amount of blade wear occurs near the side walls 40 of the drum since it is in this region where most of the ore is struck by the blades and hurled against the impact plates 48. Eventually, the ends of the beater blades 68 nearest the walls 40 become worn and when this occurs, the mill 10 is less effective in disintegrating the ore. To overcome this, the blades 68 are each formed into two equal and oblong portions 68A and 688 (FIG. 2) which are separately secured to the bars 66 by means of the bolts 69.

When excessive wear is noted on the opposite ends of the blades 68, the blade portions 68A and 68B are rearranged to avoid the necessity of replacing the entire blade as normally would be the case. To rearrange the blades 68, the milling operation need only be halted long enough to allow one of the classifier screens 46 to be removed from the peripheral wall 41 of the drum whereupon said blades are accessible. The portions 68A and 688 which make up each blade are unbolted and turned end for end so as to place the worn ends thereof at the center of the rotor 16 whereupon the portions are rebolted to the bars 66. This rearrangement doubles the operating life of the blade 68 and, when both ends of the blade portions are worn on opposite faces, the portions still have two unworn corner faces which are usable to further extend the period before the blades must be replaced with new ones.

From the foregoing it will be apparent that I have provided a lightweight and simply constructed ore mill which is most economical to operate. Adjustment of the drum 18 relative to the rotor 16 can be done without the need to shut down for lengthy periods and the arrangement is such that these two rotating members can be kept properly aligned as wear takes place on the wheels 77 and 84 or on the rings 87 which engage these wheels. Any slurry which might, escape from the drum is effectively trapped by the sealing means 100 before it can reach and harm bearings or the like and this makes the present mill a particularly easy one to maintain and operate.

I claim:

ll. An ore mill comprising a rotor having a shaft on which beater blades are mounted, a revolvable drum enclosing the rotor and having side walls and a peripheral wall, said side walls having openings through which the rotor shaft projects, said peripheral wall having circumferentially spaced screened openings and inwardly projecting impact plates, means for rotating the rotor and the drum to sweep the beater blades passed the impact plates in a cooperative, ore disintegrating motion, and mounting means for the drum, said mounting means including means for adjusting the axes of rotation of the rotor and drum radially relative to one another to vary the clearance between the beater blades and the impact plates.

2. An ore mill as claimed in claim 1 and including sealing means mounted on each side wall to seal the rotor shaft within an adjacent opening.

3. An ore mill as claimed in claim 1, in which said rotor comprises circumferentially spaced bars extending parallel to the rotor shaft, said beater blades each being formed of at least two similar and interchange able parts removably secured to a bar.

4. An ore mill as claimed in claim 1, in which said mounting means supports the drum on a base and comprises two pairs of wheels mounted on said base, a trunnion ring secured to each side wall concentric to the axis of rotation of the drum, said trunnion rings being rotatably supported on the pairs of wheels and means for adjusting one pair of wheels towards and away from the other pair of wheels.

5. An ore mill as claimed in claim 2, in which each of said sealing means comprises a cover plate slidably and non-rotatably supported against an end wall to cover the opening therein, and a small and a large annular seal interposed between each. cover plate and end wall to define a mud channel for containment of seepage escaping through the end wall opening.

6. An ore mill as claimed in claim 5, and including an annular collar secured to each side wall to enclose a large annular seal and a rim of a cover plate, said annular collars each being shaped to define a second mud channel encircling one of the first mentioned mud channels. I

7. An ore mill comprising a base, a rotor having a shaft rotatably mounted on the base and beater blades extending parallel to said shaft, a revolvable drum enclosing the rotor and having side walls and a peripheral wall, said side walls having openings through which the rotor shaft projects, said peripheral wall having inwardly projecting impact plates, two pairs of wheels mounted on the base, a trunnion ring secured to each side wall around the opening therein, said trunnion rings being rotatably supported on the pairs of wheels, means for rotating the rotor and the drum to sweep the beater blades passed the impact plates, and means for adjusting one pair of wheels towards and away from the other pair of wheels whereby to move the axes of rotation of the rotor and drum radially relative to one another and thereby vary the clearance between the beater blades and the impact plates,

8. An ore mill as claimed in claim 7 and including sealing means mounted on each side wall to seal the rotor shaft within an adjacent opening.

9. An ore mill as claimed in claim 8, in which each of said sealing means comprises a cover plate slidably and non-rotatably supported against an end wall to cover the opening therein, and a small and a large annular seal interposed between each cover plate and end wall to define a mud channel for containment of seepage escaping through the end wall opening.

10. An ore mill as claimed in claim 9, and including an annular collar secured to each side wall to enclose a large annular seal and a rim of a cover plate, said annular collars each being shaped to define a second mud channel encircling one of the first mentioned mud channels. 

1. An ore mill comprising a rotor having a shaft on which beater blades are mounted, a revolvable drum enclosing the rotor and having side walls and a peripheral wall, said side walls having openings through which the rotor shaft projects, said peripheral wall having circumferentially spaced screened openings and inwardly projecting impact plates, means for rotating the rotor and the drum to sweep the beater blades passed the impact plates in a cooperative, ore disintegrating motion, and mounting means for the drum, said mounting means including means for adjusting the axes of rotation of the rotor and drum radially relative to one another to vary the clearance between the beater blades and the impact plates.
 2. An ore mill as claimed in claim 1 and including sealing means mounted on each side wall to seal the rotor shaft within an adjacent opening.
 3. An ore mill as claimed in claim 1, in which said rotor comprises circumferentially spaced bars extending parallel to the rotor shaft, said beater blades each being formed of at least two similar and interchangeable parts removably secured to a bar.
 4. An ore mill as claimed in claim 1, in which said mounting means supports the drum on a base and comprises two pairs of wheels mounted on said base, a trunnion ring secured to each side wall concentric to the axis of rotation of the drum, said trunnion rings being rotatably supported on the pairs of wheels and means for adjusting one pair of wheels towards and away from the other pair of wheels.
 5. An ore mill as claimed in claim 2, in which each of said sealing means comprises a cover plate slidably and non-rotatably supported against an end wall to cover the opening therein, and a small and a large annular seal interposed between each cover plate and end wall to define a mud channel for containment of seepage escaping through the end wall opening.
 6. An ore mill as claimed in claim 5, and including an annular collar secured to each side wall to enclose a large annular seal and a rim of a cover plate, said annular collars each being shaped to define a second mud channel encircling one of the first mentioned mud channels.
 7. An ore mill comprising a base, a rotor having a shaft rotatably mounted on the base and beater blades extending parallel to said shaft, a revolvable drum enclosing the rotor and having side walls and a peripheral wall, said side walls having openings through which the rotor shaft projects, said peripheral wall having inwardly projecting impact plates, two pairs of wheels mounted on the base, a trunnion ring secured to each side wall around the opening therein, said trunnion rings being rotatably supported on the pairs of wheels, means for rotating the rotor and the drum to sweep the beater blades passed the impact plates, and means for adjusting one pair of wheels towards and away from the other pair of wheels whereby to move the axes of rotation of the rotor and drum radially relative to one another and thereby vary the clearance between the beater blades and the impact plates.
 8. An ore mill as claimed in claim 7 and including sealing means mounted on each side wall to seal the rotor shaft within an adjacent opening.
 9. An ore mill as claimed in claim 8, in which each of said sealing means comprises a cover plate slidably and non-rotatably supported against an end wall to cover the opening therein, and a small and a large annular seal interposed between each cover plate and end wall to define a mud channel for containment of seepage escaping through the end wall opening.
 10. An ore mill as claimed in claim 9, and including an annular collar secured to each side wall to enclose a large annular seal and a rim of a cover plate, said annular collars each Being shaped to define a second mud channel encircling one of the first mentioned mud channels. 